I submitted my original article to Dave at the end of August, and now that it is
November I have had almost three more months of acclimating to the Sun, and I am
convinced that this is one of the most controversial amplifiers in America (like the
Berning ZOTL SET)...and most will avoid it like the plague, because it will be too
upsetting of their established notions of state of the art push/pull transformer coupled
amplifiers. This the only push/pull amplifier I have ever encountered that is
causing me serious doubts about the artistic primacy of single-ended circuits.

I noticed that in the Stereophile listing of recommended tube amplifiers the only
push/pull 300B amplifier listed was the Manley Retro. This should indicate to all that
this type of circuit, which exploits a transformer phase splitter, is completely
unknown and undeveloped in America. (Remember, my job is to report from the edge)

This amplifier has given me the opportunity to know the suffering of young
Martin Luther. Am I about to proclaim a heresy? I am not sure, because I am racked with
single-ended doubt and it is because I have danced with the Devil...Riccardo Kron in the
Sun.

Let me be more accurate, the combination of some very vintage 1950s NOS 6SN7s, the new
KR 300BXL, and the VansEver Pandora tuneable line cords is creating an aural matrix that
is as unique in its own way as the aural matrix created by Berning ZOTL SET 300B and
ZH270, and by that I mean both bring me to the edge of my descriptive ability....but they
are completely different. This is very confusing because I thought I had full measure of
the Sun amps, and I was totally surprised by the transformation that occurred when I
plugged in the matched set of the new KR 300BXL tubes. Did Kron put LSD on his
tubes and then I put my fingers in my mouth?

And then when I took the extra five minutes of trouble and connected individual tube
regulated power supplies to each Sun amp I was electro-shocked into a higher dimension of
musical refinement. This is absolutely the clearest, most naturally dynamic, tonally
creamy, subtle, airy, wide and deep transformer output amplifier I have ever experienced
any where.

Has anyone in America other than me ever experienced a push/pull KR 300BXL amplifier of
this refinement? (Did you like that dig?)

So let me lay upon you a gizmological insight: Both the Berning ZH-270 and the Sun amps
are minimalist designs: both use only two tubes per channel. Over the decades of
experimentation with amplifiers of all genres, including the Futterman and AtmaSpheres, I
found that less tubes equaled greater clarity and harmonic whole-osity. Of course in my
case power is not a consideration so I will always go for less is more in an
output stage.

We the gifted listeners of America, the lunatic fringe of the thermionic revolution,
have been rightly critical of the high price paid for big horsepower
push/pull/pentode/high feedback amplifiers that make most audio reviewers drool with
power, and it is safe to say that less than .01% Americans know that there is another
way...and it is the Japanese way....which is an update of what America was into in the
late 1930s.

Can I blame my favorite target once again? The reason that the American audio arts have
stalled is because we can not yet get the right type of speakers...those which reveal the
nascent subtle of our tube circuits....or to put it another way...speakers designers have
fallen way behind thermionic techno-shamans.

Now lets have a slice of hot apple pie so I can be very pieous. If you come from
the normal single-ended school and you hear a Berning ZOTL SET amplifier
you immediately recognize that you have been missing the lowest and highest
octaves. This is the price we pay for the midrange ecstasy of the directly heated
single-ended triode with transformer output amplifiers. Yet, even the Berning SET ZOTL
suffers in comparison to the Berning ZH-270 push/pull amplifier in lower octave
dynamics...again the advantage will always go to push/pull circuits in this regard. The
reason I mention this is if you are a single-ended addict like me, when you experience the
Sun or ZH-270 you immediately realize that you have been missing something...the frequency
extremes, and the dynamic coherence top to bottom that is only possible with refined
push/pull amplifiers. And the other quality that is apparent and obvious
is...yes...push/pull cancels a certain type of distortion and when going back to
single-ended circuits...even my own custom jobs....you begin to wonder.......

Because I am so impressed by this amplifier I am going to do something that I rarely
do....and I am doing this in the hope of stimulating your creativity. I am going to
quickly analysis each aspect of this amplifier that may be contributing to is ORGANIC
UNITY...but remember, it is the gourmet blending that creates the magic. I am repeating
what I stated in my full article but it is worth repeating, so you can make a check list:

(1) 300B push/pull output stage: As far as I know only Cary Audio and VAC are making
push/pull amplifiers with this tube, but Sun runs their tubes at only 320 Volts, and I
believe they are run pure Class A, which yields only 20 watts; thereby sacrificing power
to eliminate the NOT refinement of the more efficient AB1. (Emerging from the fog of my
pre-Futterman push/pull days is my belief that my favorite pentode, the EL 34 sounded best
running at 330 volts/Class A). I suspect that this is a very low distortion point for
300Bs and especially the KR tubes, but I cant be sure. I also need to point out that
the filaments of 300Bs are run with AC, and a hum balance control, which, according to the
purist, gives superior sonics over DC on the filaments. And most importantly I am
experiencing the quality of the Tamura transformers.

Very few, because of the single-ended craze, have heard 300Bs in push/pull which
reveals some extraordinary qualities that SET dont reveal. But again, the KR
300BXL is a triode of completely different nature than all other brands of 300Bs...even
the Western Electric. The combination of dynamics, low distortion, full frequency dynamic
wave front, and tonal refinement will be a unique thrill for directly heated triode fans.
This makes we wonder what the Sun 2A3 push/pull amplifier would sound like with the new
KR 2A3s which are very impressive.

In regards to the Western Electric 300Bs...when used in the Sun, they approach much
more closely the midrange magic of single-ended circuits which have an intensity of
musical cream in the midrange that totally dominates the aural matrix....so....if you want
you Suns to sound more like a classic single-ended circuit use the Western Electric 300Bs.

Why Audio Research, Conrad Johnson, Sonic Frontier, and Golden Tube Audio dont
create 300B push/pull amplifiers is beyond the beyond in terms of doing the right thing.
And neither the Cary or VAC amps are an attempt at the edge of the art. Of course none of
the tube manufacturers...neither Sovtek, Svetlana, Western Electric or KR are pushing
this...so what can we expect when not even the worlds leading tube entrepreneurs
have not yet explored push/pull directly heated triodes?

(2) Chokes: This ancient form of power supply filtration is so essential for optimal
operation short of an active regulator. Nothing better indicates the general primitive
state of American tube design than the almost total absence of choke filtered power
supplies. Of course Sun uses a choke, and that matters a great deal.

(3) Power supply capacitors: Not normal aluminum electrolytics, but the
more advanced form of Cerafine capacitor here. My experiments with oil capacitors in
parallel with these indicated that there is an improvement, but they are so large, even
for their small value, that external chassis would be needed. At New York Audio Labs we
used to use very large polypropylene motor start capacitors in parallel with aluminum
electrolytic used in all Moscode amplifiers and it made a big difference. The Futterman
amplifier only used photo-flash capacitors in their power supplies which were very
different that the aluminum types. Obviously Mr. Uchida knows what he is doing.

(4) Transformer phase splitter/no coupling capacitor: Of all of the elements of this
amplifier this is the one that stands out, so let me get to the point: When I heard this
amp, it was as different as my first experience of the Futterman OTL amplifier...compared
to my 1979 reference amplifier. Something very unique and positive is present here, and
Tamura has created a true work of art in this tiny little transformer phase splitter.
Smart American tube amplifier designers will immediately order some and start
experimenting with them....but that assume a degree of artistic maturity that is rare in
America.

(5) Less is More Voltage amplifier: Using a medium mu dual triode 6SN7 with both
sections in parallel does NOT yield much gain in this circuit, and others who use
transformer phase splitter often use voltage amplifier circuits with higher gain, so my
intuition is telling me that the aroma of this tube is important. Based on my
experimentation with five or six different NOS 1950s brands I can confirm that there is an
alchemy between the tone of this tube with the 300B family. I love the sound of RCA.

(6) Tube rectification: No solid state rectifiers to screw up the tone here. I
cant wait until the new version of the Western Electric 274 and KR 274 is available
because I believe that this will advance the sound of the stock amplifier. I can alter the
tone of this amplifier by changing brands of rectifiers and this is very desirable. Change
the brand of rectifier, shift the tone of the circuit.

(7) Tamura Iron: I am not going to repeat myself here other than to say...you owe to
yourself to experience this level of transformer quality, but it is an exercise only for
the ego secure because it will depress those who erroneously believe that American tube
amplifiers are using the highest quality iron.

(8) Parts Quality: The simpler the circuit, and this is absolutely the simplest
push/pull circuit, the more the quality of parts matter, and this amplifier maxes out on
parts quality. Every time a friend comes to my house I take the bottom plate off this
amplifier to show them the beauty of its construction. A Japanese artist soldered all of
parts and did all of the hardwiring, and it is thrilling to gaze at this level of build
quality...it is like gawking at a Ferrari motor....only better.

GETTING TO THE POINT: Contact Suns distributor Yong Kim and get the Sun
and Tamura catalog, go to Sun Audio web site and check out what the Uchida family is
into...it is very major.

When you check out the Sun catalog check out their phono preamp, which is a completely
unique circuit, and I hope, I dream , that I can convince Mr. Uchida to send one to me so
I may explore the other half of Suns genius.

Anyone who is interested in experiencing the highest level of single-ended bliss would
be wise to explore the Sun single-ended circuits because evertyhing that I have said about
their push/pull amplifiers must apply to their single-ended circuits. Those who are
looking for absolutely the ultimate amplifier for their Lowthers should check out
their 2A3 circuits, and make sure you use the KR 2A3 tubes.